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Call for ContributionsHETEROCYCLES Special Issue Vol. 99 in honor of Professor Tohru Fukuyama on 70th Birthday

Submission deadline: September 10, 2018
On the occasion of Professor Tohru Fukuyama's 70th birthday, HETEROCYCLES editorial office is planning to publish special anniversary issue on April 1, 2019 as Vol. 99. Authors are invited to submit their work to this topical issue.
Authors wishing to submit their manuscript should contact editorial office via e-mail by the end of May, 2018. Manuscript should reach the editorial office no later than September 10, 2018.
Contact: submit@heterocycles.com

March 5, 2018

Heterocycles Award
HETEROCYCLES is pleased to announce Heterocycles Award.
In recognition of an outstanding oral presentation at the 47th Congress of Heterocyclic ChemistrySee more

December 13, 2017

Call for ContributionsHETEROCYCLES Special Issue Vol. 97 in honor of Professor Kiyoshi Tomioka on 70th Birthday

Submission deadline: February 15, 2018
On the occasion of Professor Kiyoshi Tomioka's 70th birthday, HETEROCYCLES editorial office is planning to publish special anniversary issue on September 1, 2018 as Vol. 97. Authors are invited to submit their work to this topical issue.
Authors wishing to submit their manuscript should contact editorial office via e-mail by the end of November, 2017. Manuscript should reach the editorial office no later than February 15, 2018.
Contact: submit@heterocycles.com

■ Direct Routes to 2H-Tetrazoles by Cyclization and Ring Transformation

Abstract

This review summarizes the known routes to the title compounds that were formed from cyclization of open-chain precursors and ring transformation of non-tetrazolic heterocycles, i.e. procedures that are not based on ring substitution of the corresponding N-unsubstituted tetrazoles.

Abstract

The reaction of helical quinone with thiols in the presence of Brønsted acid such as HCl, para-toluene sulfonic acid (pTSA), Yb(OTf)3·3H2O or BF3·OEt2 to form resulted in the formation of thioalkoxy-substituted oxa[9]helicenes in moderate to good yields.

Abstract

Derivatives of two novel heterocyclic ring systems were synthesized and their affinities for dopamine receptors were measured. The compounds were obtained by reacting histamine with 2-(2-bromoethyl)benzaldehyde including an atypical Pictet-Spengler condensation, which afforded basic and not the usual neutral or acidic conditions. The resulting imidazo[4',5':3,4]pyrido[2,1-a]-isoquinoline derivative 4 was Boc protected at the most basic imidazole nitrogen, the isoquinoline nitrogen then quaternized by using methyl iodide and the tetracyclic isoquinolinium salt was both deprotected and cleaved under Birch conditions in one step to give a tricyclic imidazo[4,5-f][3]benzazecine derivative (3) by opening two 6-membered heterocycles towards one 10-membered. Radioligand binding studies showed a significant affinity of the moderately constrained 3 but not of 4 for dopamine receptors. Similar to the analogous indolo-benzazecine LE300, a preference of 3 for the D1 receptor family was observed, but with some loss of affinity over all.

Abstract

The efficient one-pot condensation of aldehyde, dimedone, and phthalhydrazide has been achieved in the presence of a catalytic amount of Fe(III)-based dicationic ionic liquid, [C4(mim)2](FeCl4)2, as a novel environmentally benign magnetic catalyst under solvent-free conditions. The catalyst was easily separated after completion of the reaction and was recycled four times without affecting the catalytic property.

Abstract

The oxidation of 4-substituted urazoles to the corresponding 1,2,4-triazoline-3,5-diones can be performed selectively in the presence of dienic systems by the action of the nitrosonium ion, formed in situ by stoichiometric amounts of sodium nitrite and acetic acid. This convenient methodology is mild, fast, and allows the efficient protection of dienic systems in a one-pot procedure. The dienes were not affected whatsoever by the nitrosonium ion, and react extremely fast with triazolinediones; promptly forming the corresponding Diels-Alder cycloadducts in good to excellent yields. The reaction medium did not affect steroids having an extra double bond at the side chain or an acid-labile spiroketal moiety.

Abstract

One new aurone, one new isoaurone, damaurones A and B (1 and 2), and five known compounds (3-7) were isolated from the flowers of Rosa damascena. Their structures were elucidated by spectroscopic methods, including extensive 1D- and 2D- NMR techniques. Compound 1 is the first naturally occurring aurone derivatives bearing an acetyl group. Compounds 1-7 were tested for their anti-HIV-1 activities and cytotoxicities. The results showed that compound 1 has significant potential anti-HIV-1 activity with therapeutic index (TI) values above 80, and showed high cytotoxicities against NB4 and MCF7 cell with IC50 values of 3.4 and 2.6 μM, respectively.

Abstract

A convenient synthesis of spirothiazolidinones by nucleophilic cyclocondensation of intermediate imine with mercaptoacetic acid is described. Computational studies have been performed to substantiate the proposed mechanism as well as to ascertain transition state of the system.

Abstract

The Diels-Alder reaction between diethyl 1-phosphono-1,3-butadiene and cyclic azo dienophiles, such as 4-phenyl- and 4-methyl-1,2,4-triazoline-3,5-diones and phthalazine-1,4-dione gave access to phosphonated bicyclic cycloadducts with a nitrogen-nitrogen junction. Various fonctionalizations (dihydroxylation, hydrogenation and phosphonic ester deprotection) have been performed with success. The selective N-N cleavage was not possible for the preparation of large heterocycles. The coordination properties of selected bicycles were tested by ESI-HRMS.

Abstract

Two novel bisindole alkaloids, cyclovinblastine A-B (1-2), together with ten known alkaloids 4-deacetoxycyclovinblastine (3), cycloleurosine (4), leurosine (5), vinblastine(6), leurosidine(7), vinblastine N'b-oxide (8), isoleurosine (9), 4'-deoxyleurosidine(10), 4'-deoxyleurosidine N'b-oxide(11) and 4-desacetoxyvinblastine(12) were isolated from the leaves of Catharanthus roseus. The structures of 1 and 2 were established by analysis of their NMR and HR-ESI-MS spectroscopic data. All alkaloids (1-12) were evaluated for their cytotoxic activities against the human hepatocellular carcinoma (HepG2) cell line, human colorectal carcinoma (Lovo) cell line, and human breast carcinoma (MCF-7) cell line by the MTT method in vitro, respectively. The results indicated that cytotoxic activities of alkaloids 9, 10 and 12 were much more potent than those of the positive control vinblastine (6). In addition, the structure-activity relationships (SAR) were conducted on the basis of the cytotoxicity of these isolated alkaloids.

■ Isolation and Structure Elucidation of Alkaloids from Pinellia ternata

Abstract

A new compound, 3-(6,7-dimethoxyisoquinolin-1-yl)-4,7-dimethoxy-3-methylisobenzofuran-1(3H)-one (1) named alkterlactone was isolated from Pinellia ternata, together with four known compounds N-trans-feruloyloctopamine (2), 2'-O-methyladenosine (3), 5'-S-methyl-5'-thioadenosine (4) and 2'-deoxy-thymidine (5). Compounds 2–5 were isolated for the first time from Pinellia ternata. The structures of these compounds were elucidated and characterized on the basis of 1D NMR, 2D NMR and MS data.

Abstract

Two new peptaibols, asperelines G (1) and H (2), together with five known compounds, asperelines A (3), C (4), D (5), E (6), and F (7) were isolated from the marine-derived fungus Trichoderma asperellum. The structures of these compounds were determined through spectroscopic methods, X-ray diffraction analysis, and chemical derivatization. This study is the first report on asperelines with an acetylated C-terminus and a crystal structure.

■ Synthesis of Pyrazoles through Copper-Catalyzed Three-Component Coupling of Aldehydes, Alkynes, and p-Toluenesulfonylhydrazide

Abstract

A convenient one-pot synthesis of 3,5-disubstitued 1H-pyrazoles through copper-catalyzed three-component of aldehydes, alkynes, and para-tolylsulfonohydrazide has been developed. This method provides a flexible and rapid route to 3,5-disubstituted 1H-pyrazoles.

Abstract

We describe the synthesis and chemical properties of newly designed C2-symmetrical twin-drug type aminoguanidines or 4-aminomethyloxazolidinone derivatives (4-7) in which a long chain alkyl group [-(CH2)10-] was used as a linker. Synthesis of some triplet-drug type symmetrical oxazolidinones (8) is also described. Among the tested compounds, the aminoguanidine derivative 4a showed the highest α-glucosidase inhibition activity (IC50 = 76.3 μmol/L).